Electric telephone



No Model) 0.1". DUNDERDALE.

ELECTRIC TELEPHONE. No. 585,560. Patented June 29,1897.

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CLEAVELAND F. DUNDERDALE, OF CHICAGO, ILLINOIS, ASSIGNOR, BY DIRECT ANDMESNE ASSIGNMENTS, TO TIIE AUTOMATIC LONG DISTANCE TELEPHONE COMPANY, OFILLINOIS.

ELECTRIC TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 585,560, dated June 29,1897.

Application filed January 7, 1895. Serial No. 584,083. (No model.)

T0 to whom it may concern.-

Be it known that I, CLEAVELAND F. DUN- DERDALE, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inElectrical Telephones, of which the following is a specification.

My invention relates to certain improvements in a telephoiieswitcli; andit consists in an arrangement and construction whereby the switchingdevice is disposed Within the end of the hand-receiver and operated inthe manipulation of the said receiver.

Reference may now be had to the accompanying drawings, in which- Figure1 is a front view of a transmitter and a vertical central sectionthrough the handreceiver, which latter is shown supported upon thetransmitter. Fig. 2 is a view of a portion of the hand-receiver brokenaway and in section at its end to show another position of thecircuit-changer or switching device in the end of the receiver. Fig. 3is an end view of the receiver, the cap-piece being removed. Fig. 4; isa sectional view on the line y y of Fig. 1.

I provide a plurality of magnets 23, each one of which has its enddisposed in proximity to the outer edge of the diaphragm 24, secured toa ring 25, seated within the casing 26 by being screw-threaded to ahousing-ring 27, set and held within said casing, so that these magnetsmay be adjusted toward or away from the diaphragm 24 by manuallyrotating them bodily and thus rotating the ring 25 on the ring 27through the medium of the screw-thread connections between them.

Having reference now to the features of my invention which resideparticularly in the means for establishing or disestablishing contactand circuits, I provide a supporting-hook 29, projected from thetransmitter-box 30, which hook, however, is not employed for switchingpurposes. The automatic switch or circuit-changer is located in that endof the receiver opposite to the diaphragm and c011- sists of twoconducting-rings 29 and 30, located in a cap 31, that screws into abushing 32, which latter in turn screws into the end of the receiver.These two conducting-rings 29 and 30 are insulated from one another, andthe plate 29 is connected with the lead 33 to the transmitter 34., andthe ring 30 is connected with the helices 28 by the lead 35, whichhelices are also connected with the lead 36 to the exchange by thebranch lead 37. The bushing 32 has an apex cavity within which twocontact-plates 38 and 39 are disposed and separated from one another byan insulating-partition t0, the plate 39 being connected with the lead36 to the exchange and the plate 38 being connected with the lead ll tothe ringing apparatus 42.

When the receiver is hung upon the hook 29 in an inverted position, ametal ball 43 rests upon the two plates 38 and 39 within the apex-shapedcavity and thus maintains continuity of circuit between the exchange andthe ringing apparatus 42, so that the subscriber may signal either tothe exchange or to another instrument without removing the receiver fromthe hook 29. hen, however, the subscriber removes the receiver from thehook and holds the same to the ear in that natural position assumed whenused for listening purposes, the contact-ball 43 then rolls out of theapex-shaped cavity into a position between the two conducting-rings 29and 30 and thereby establishing continuity of circuit between thehelices 28 and the transmitter 34.

It is obvious that this type of automatically-operating circuit-changermay be em ployed in conjunction with any type of tele phone or telephonesystem, and is not limited to its use in conjunction with amagnetotelephone.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is

In a telephone-receiver a gravity-switch therefor consisting of achamber divided into two compartments, located in the interior end ofthe receiver, a movable-ball contact-maker normally resting within onecompartment of the chamber when the receiver is not in use, leads of thesignaling-circuit terminating in said compartmentwhereby the saidcircuit is normally completed by said movable-ball con- IOO tact andleads of the talking-circuit terminat- In testimony whereof I ztffix mysignature ing in the other compartment of said eh amber in presence oftwo witnesses. whereby when the recelver 1s tllted 111 use theCLEAYELASD R DUNDERDALE movable-ball Contact shifts from one c0mp2trt- 5ment into the other thereby disestabhshing Witnesses:

the signaling-circuit and establishing the CHAS. C. BULKLEY,talking-circuit. C. \V. GRAHAM.

